// Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "base/strings/string_piece.h" #include #include #include #include #include #include "base/strings/utf_string_conversions.h" #include "build/build_config.h" namespace base { namespace { // For each character in characters_wanted, sets the index corresponding // to the ASCII code of that character to 1 in table. This is used by // the find_.*_of methods below to tell whether or not a character is in // the lookup table in constant time. // The argument `table' must be an array that is large enough to hold all // the possible values of an unsigned char. Thus it should be be declared // as follows: // bool table[UCHAR_MAX + 1] inline void BuildLookupTable(StringPiece characters_wanted, bool* table) { const size_t length = characters_wanted.length(); const char* const data = characters_wanted.data(); for (size_t i = 0; i < length; ++i) { table[static_cast(data[i])] = true; } } } // namespace // MSVC doesn't like complex extern templates and DLLs. #if !defined(COMPILER_MSVC) template class BasicStringPiece; template class BasicStringPiece; template class BasicStringPiece; #endif std::ostream& operator<<(std::ostream& o, StringPiece piece) { o.write(piece.data(), static_cast(piece.size())); return o; } std::ostream& operator<<(std::ostream& o, StringPiece16 piece) { return o << UTF16ToUTF8(piece); } std::ostream& operator<<(std::ostream& o, WStringPiece piece) { return o << WideToUTF8(piece); } namespace internal { template size_t findT(T self, T s, size_t pos) { if (pos > self.size()) return BasicStringPiece::npos; typename BasicStringPiece::const_iterator result = std::search(self.begin() + pos, self.end(), s.begin(), s.end()); const size_t xpos = static_cast(result - self.begin()); return xpos + s.size() <= self.size() ? xpos : BasicStringPiece::npos; } size_t find(StringPiece self, StringPiece s, size_t pos) { return findT(self, s, pos); } size_t find(StringPiece16 self, StringPiece16 s, size_t pos) { return findT(self, s, pos); } template size_t rfindT(T self, T s, size_t pos) { if (self.size() < s.size()) return BasicStringPiece::npos; if (s.empty()) return std::min(self.size(), pos); typename BasicStringPiece::const_iterator last = self.begin() + std::min(self.size() - s.size(), pos) + s.size(); typename BasicStringPiece::const_iterator result = std::find_end(self.begin(), last, s.begin(), s.end()); return result != last ? static_cast(result - self.begin()) : BasicStringPiece::npos; } size_t rfind(StringPiece self, StringPiece s, size_t pos) { return rfindT(self, s, pos); } size_t rfind(StringPiece16 self, StringPiece16 s, size_t pos) { return rfindT(self, s, pos); } // 8-bit version using lookup table. size_t find_first_of(StringPiece self, StringPiece s, size_t pos) { if (self.size() == 0 || s.size() == 0) return StringPiece::npos; // Avoid the cost of BuildLookupTable() for a single-character search. if (s.size() == 1) return self.find(s.data()[0], pos); bool lookup[UCHAR_MAX + 1] = { false }; BuildLookupTable(s, lookup); for (size_t i = pos; i < self.size(); ++i) { if (lookup[static_cast(self.data()[i])]) { return i; } } return StringPiece::npos; } // Generic brute force version. template size_t find_first_ofT(T self, T s, size_t pos) { // Use the faster std::find() if searching for a single character. typename BasicStringPiece::const_iterator found = s.size() == 1 ? std::find(self.begin() + pos, self.end(), s[0]) : std::find_first_of(self.begin() + pos, self.end(), s.begin(), s.end()); if (found == self.end()) return BasicStringPiece::npos; return static_cast(found - self.begin()); } size_t find_first_of(StringPiece16 self, StringPiece16 s, size_t pos) { return find_first_ofT(self, s, pos); } // 8-bit version using lookup table. size_t find_first_not_of(StringPiece self, StringPiece s, size_t pos) { if (pos >= self.size()) return StringPiece::npos; if (s.size() == 0) return pos; // Avoid the cost of BuildLookupTable() for a single-character search. if (s.size() == 1) return self.find_first_not_of(s.data()[0], pos); bool lookup[UCHAR_MAX + 1] = { false }; BuildLookupTable(s, lookup); for (size_t i = pos; i < self.size(); ++i) { if (!lookup[static_cast(self.data()[i])]) { return i; } } return StringPiece::npos; } // Generic brute-force version. template size_t find_first_not_ofT(T self, T s, size_t pos) { if (self.size() == 0) return BasicStringPiece::npos; for (size_t self_i = pos; self_i < self.size(); ++self_i) { bool found = false; for (auto c : s) { if (self[self_i] == c) { found = true; break; } } if (!found) return self_i; } return BasicStringPiece::npos; } size_t find_first_not_of(StringPiece16 self, StringPiece16 s, size_t pos) { return find_first_not_ofT(self, s, pos); } // 8-bit version using lookup table. size_t find_last_of(StringPiece self, StringPiece s, size_t pos) { if (self.size() == 0 || s.size() == 0) return StringPiece::npos; // Avoid the cost of BuildLookupTable() for a single-character search. if (s.size() == 1) return self.rfind(s.data()[0], pos); bool lookup[UCHAR_MAX + 1] = { false }; BuildLookupTable(s, lookup); for (size_t i = std::min(pos, self.size() - 1); ; --i) { if (lookup[static_cast(self.data()[i])]) return i; if (i == 0) break; } return StringPiece::npos; } // Generic brute-force version. template size_t find_last_ofT(T self, T s, size_t pos) { if (self.size() == 0) return BasicStringPiece::npos; for (size_t self_i = std::min(pos, self.size() - 1); ; --self_i) { for (auto c : s) { if (self.data()[self_i] == c) return self_i; } if (self_i == 0) break; } return BasicStringPiece::npos; } size_t find_last_of(StringPiece16 self, StringPiece16 s, size_t pos) { return find_last_ofT(self, s, pos); } // 8-bit version using lookup table. size_t find_last_not_of(StringPiece self, StringPiece s, size_t pos) { if (self.size() == 0) return StringPiece::npos; size_t i = std::min(pos, self.size() - 1); if (s.size() == 0) return i; // Avoid the cost of BuildLookupTable() for a single-character search. if (s.size() == 1) return self.find_last_not_of(s.data()[0], pos); bool lookup[UCHAR_MAX + 1] = { false }; BuildLookupTable(s, lookup); for (; ; --i) { if (!lookup[static_cast(self.data()[i])]) return i; if (i == 0) break; } return StringPiece::npos; } // Generic brute-force version. template size_t find_last_not_ofT(T self, T s, size_t pos) { if (self.size() == 0) return StringPiece::npos; for (size_t self_i = std::min(pos, self.size() - 1); ; --self_i) { bool found = false; for (auto c : s) { if (self.data()[self_i] == c) { found = true; break; } } if (!found) return self_i; if (self_i == 0) break; } return BasicStringPiece::npos; } size_t find_last_not_of(StringPiece16 self, StringPiece16 s, size_t pos) { return find_last_not_ofT(self, s, pos); } size_t find(WStringPiece self, WStringPiece s, size_t pos) { return findT(self, s, pos); } size_t rfind(WStringPiece self, WStringPiece s, size_t pos) { return rfindT(self, s, pos); } size_t find_first_of(WStringPiece self, WStringPiece s, size_t pos) { return find_first_ofT(self, s, pos); } size_t find_first_not_of(WStringPiece self, WStringPiece s, size_t pos) { return find_first_not_ofT(self, s, pos); } size_t find_last_of(WStringPiece self, WStringPiece s, size_t pos) { return find_last_ofT(self, s, pos); } size_t find_last_not_of(WStringPiece self, WStringPiece s, size_t pos) { return find_last_not_ofT(self, s, pos); } } // namespace internal } // namespace base